Isuzu N-Series. Manual - part 1021

CAB AND CHASSIS ELECTRICAL 8-189

Diagnosis

Quick Chart for Check Point
1. Turn Signal Light, Hazard Warning Light

Notice:
Figure in parenthesis “( )” indicates the order of inspection.

2. Stoplight

Notice:
Figure in parenthesis “( )” indicates the order of inspection.

Check point

Fuse

Turn 

signal 

light SW

Hazard 

warning 

light SW

Flasher 

unit

Turn 

signal 

light bulb

Cable 

harness

F-19, F-20

(15 A)

F-11

(10 A)

Trouble
mode

1-1. Turn signal lights 
inoperative

❍

❍

❍

❍

1-2. Turn signal lights 
flash too quickly

❍

❍

1-3. Hazard warning 
lights inoperative

❍

❍

Check point

Fuse

F-5 (10 A)

Stoplight SW

Stoplight bulb

Cable harness

Trouble
mode

2-1. Both stoplights inoperative

❍

❍

❍

2-2. Stoplight on the left (or right) 
side inoperative

❍

❍

8-190 CAB AND CHASSIS ELECTRICAL

1. Turn Signal Light, Hazard Warning Light
1-1. Turn Signal Lights Inoperative

N8A0169E

CAB AND CHASSIS ELECTRICAL 8-191

1-2. Turn Signal Lights Flash Too Quickly

• IS THERE ANY CONTINUITY BETWEEN THE HARNESS

SIDE CONNECTORS 3  B-16  AND  B-7  ?

GROUND IT SECURELY

CONTINUED FROM THE PREVIOUS PAGE

CONTINUED FROM THE PREVIOUS PAGE

• DISCONNECT THE COMBINATION SWITCH

CONNECTOR

• IS THERE ANY CONTINUITY BETWEEN THE SWITCH

CONNECTORS 5  B-70  AND 12  B-70  (WHEN 
TURNING LEFT), 13  B-70  AND 12  B-70  (WHEN
TURNING RIGHT) RESPECTIVELY?

YES

NO

REPAIR A POOR CONNECTION AT THE
CONNECTORS OR AN OPEN CIRCUIT BETWEEN
THE CIRCUIT

• REPAIR A POOR CONNECTION AT THE CONNECTORS

OR AN OPEN CIRCUIT BETWEEN THE HARNESS SIDE
CONNECTORS 2  B-16  (12V), 5  B-16  (24V) AND 
12  B-70  

YES

NO

REPAIR OR REPLACE THE SWITCH

N8A0170E

• DOES ANY TURN SIGNAL LIGHT REMAIN

UNLIGHTED?

YES

DISCONNECT AND REINSTALL THE BULB, OR
REPLACE IT, OR REPAIR AN OPEN CIRCUIT IN
THE CIRCUIT OF THE INOPERATIVE BULB, OR
CHECK THE GROUND

N8A0171E

8-192 CAB AND CHASSIS ELECTRICAL

1-3. Hazard Warning Lights Inoperative

2. Stoplight
2-1. Both Stoplights Inoperative

• IS FUSE  F-19  ,  F-20  (15A) NORMAL?

• DOES THE HAZARD WARNING LIGHT SWITCH

FUNCTION NORMALLY?

YES

NO

REPLACE THE FUSE

• REPAIR A POOR CONNECTION AT THE CONNECTORS

OR AN OPEN CIRCUIT BETWEEN FUSE  F-19  ,  F-20   (15A) 
AND 1  B-30 

YES

NO

REPLACE THE HAZARD WARNING LIGHT
SWITCH

N8A0172E

• IS FUSE  F-5  (10A) NORMAL?

• IS  J-9  GROUNDED SECURELY?

YES

NO

REPLACE THE FUSE

• IS BATTERY VOLTAGE APPLIED TO THE 1  B-66  OF

THE STOPLIGHT SW?

YES

NO

GROUND IT SECURELY

• IS STOPLIGHT SWITCH NORMAL?

YES

NO

REPAIR A POOR CONNECTION AT THE
CONNECTORS OR AN OPEN CIRCUIT BETWEEN
THE FUSE  F-5  (10A) AND 1  B-66 

YES

NO

• DOES THE PUSH ROD OF THE STOPLIGHT SW

OPERATE SMOOTHLY?

REPLACE THE STOPLIGHT SW

REPAIR A POOR CONNECTION AT THE CONNECTORS
OR AN OPEN CIRCUIT BETWEEN 2  B-66  AND  J-9  

YES

NO

REPLACE THE STOPLIGHT SW

N8A0173E